This doesn't help much with the Solo or Elites, obviously, but something I've done to speed up battles:
Assume all normal monsters are minions unless they successfully hit a PC and thus 'earn' staying time. If the PCs get initiative, the first few monsters they hit are all minions. It simulates the heroes charging in and immediately stomping heads. It also means that foes who roll well or do something interesting always stick around for the fight - it provides extra in-character 'frustration.' To me, there's nothing worse than getting dropped by a minion or having a minion do something really awesome and then fold up. Using this method front-loads the encounters so that a lot of bodies hit the floor fast, removing that boring clean-up phase at the end.
As for Solos and Elites.. not sure. Probably knock off 20% of their HP off the top and apply a blanket -2 when bloodied.