I have three mini heads that I like a lot.
1) Mesa Boogie Mark V:25: This one is great, may miss a bit of the grunt of the larger Mesas, but has plenty of punch and tone. Has a 25-watt and 10-watt mode.
2) Victory Kraken: Maybe a little hard to find state-side, but it's compact and can go up to 50 watts, though it has a half power mode and even a 1-1/2 watt mode. Kind of like a British 5150.
3) PRS Archon 25: This amp is a beast. I only acquired it a couple of months ago, but it has grown on me. Such oversized tone for a 25-watt combo. Has a half power mode (13W). While most people don't like Celestion G12T-75 speakers, the pairing in the combo is something special.
You may be able to find them used within your price range, so don't jump at the first ad you see and be prepared to play a waiting game.
There's also one more amp that I have heard really good stuff about: the Peavey 6505MH. Supposed to be a real monster and is available new at under $499. You should be able to find a used one for about half your budget, and then be able to spend the rest on getting a good cab to go with it.
Happy hunting!