gawd, I'd hate to work in that environment. Truly the only solution I'd ever recommend is running the drops required. 6500s are sweet, but it sounds like you're environment would benefit from the cost savings of 3750s with the 32Gbps stackwise cables in between. Onsies/twosies (i know) of users with their own hubs I'd consider, but not mass deployment.
Once thing to understand is you just might be having network loops allowing that. Even if you have 6513s or some GSR in the closet - you put a hub at the user's desk and they create a loop it does no good. If you do homeruns from their work area, to a nice managed switch (even if it is not Cisco) - the switch will detect loops and stp will block a port to save your ass.
There are many solutions that'll drastically increase performance and reliability from your existing infrastructure. From my point of view, what you're doing is something I'll never recommend.
My '03 Sold.