CrimsonTide
I am currently at one of the top 3 consulting firms, and have consistently been a top performer. I have received feedback from my managers along the lines of "strongest analyst I have ever worked with", "skill set way beyond your years", "this is the best review I have ever written" etc. I have consistently been in the "top band" of my cohort, and as a result have had the opportunity to do some pretty interesting work.
My questions are the following:
1) Most of my projects have been 4-8 weeks. OK to get recommendations from someone who has only managed me for that long?
2) Is there any strategy to get recommendation letter writers to include this high praise in the recommendations?
3) Will it have high impact, given most recommendations are probably strongly positive anyway. Any way to set myself apart?
4) Anything else I can do to show my strong performance (mention consistently high review scores, %ile etc.?) Where?
5) What are my general chances (profile below) - targeting HBS (top choice), Stanford GSB, Wharton
6) Company does not officially sponsor until after acceptance, but I have been verbally told I will be sponsored. Where can I show this?
Background: Indian citizen/25; high school in a foreign country; then college at a selective public school (Berkeley/UVA/UCLA/Michigan/UT etc.)
Major: Business and Computer Science
GPA: 3.5/4.0
GMAT: 720
Full-time work experience: MBB in the US (3 years at matriculation - 2 years as analyst, 1 year as associate)
Internship experience: Another top consulting firm, top tech firm (Google/MSFT/IBM/Cisco/Intel), and a F100 company
Story: Obsessed with consumer behavior in different global markets. At my consulting firm, by matriculation will have spent a year each on projects in the US, Asia and Europe (total of 11 countries over 2.5 years). Have focused my work on consumer and retail. Strongly think that each and every international experience has helped my further my entire world view, and love the art and science of understanding consumer decision making. My senior thesis in college was an economics paper on consumer behavior. Post-MBA goal is to go back to my current firm, and eventually join a CPG/retail company with the aspiration of becoming a country manager for an emerging market
Extracurriculars: research in college (tech/data-mining), varsity sports (less common sport), president of a couple marketing/consulting clubs
Thank you for taking the time to respond

Wow, what a profile. Honestly not too sure why you would post here if you're coming from an MBB. Typically those firms send so many people to business schools and hire so many people from business schools that I'd expect most people coming from there to have a significant support network formal or informal.
Question though, if you've already been promoted beyond a BA to an associate position, then why the MBA? I think many schools admissions officers will ask this question as well.
Here are my fully unqualified answers to your questions:
1) I think because of the nature of your work (intense projects spanning 4-8 weeks) you should be ok here. It may be helpful to find individuals that you've worked on multiple projects with, but I think if it's someone that's directly managed you, they should be qualified to give you an adequate recommendation. It may also help to get one from a client that you may have worked with on several projects with as well.
2) I guess the strategy would be to ask them to make sure they include comments like the ones you've already heard. Like I stated previously, many people from your firm either came from or is used to sending people to top business schools. I'm sure they're already familiar with the process and they'll likely write an amazing recommendation. It also doesn't hurt to prep them anyways, just look around this forum or elsewhere online for suggestions.
3) I don't think in this scenario you can "set yourself apart" with a recommendation aside from having them write that you are one of the best in your cohort. The only other ways that you can really set yourself apart from your peers would be your extra-curriculars and other professional accomplishments. Those types of aspects can help distinguish you from an already highly competitive pool.
4) Strong performance can be shown through impact and useful anecdotes. That's what the essay portion of the application is for.
5) Here I am absolutely not qualified to give you a good assessment. But if I were to randomly pick percentages from the blank space behind this computer I'd say H/S/W is ~10% based on the information you've provided here.
6) Why would you want to show this? I don't think it would have a significant impact on your application decision. And anyways, these schools accept so many people from MBB that they are likely intimately familiar with your firm's internal policies.
IMO, I'd say that you definitely have an edge up as far as work experience goes (double gold stars for MBB and excellent reviews), but a 720 GMAT (although typically a great GMAT score!) is below average for H/S/W and being from an over-represented demographic doesn't help.
You definitely check off all of the minimum boxes for things that they're looking for, but it'll be your EC's and impact that'll help your chances.

Disclaimer: This is all just my unqualified opinion...