I'm not sure if this would meet your size requirements or not but I have had very good luck with my Alpine MRP F-550. I have found it to be an extremely versatile and forgiving 4ch class A/B amp. Running in 3ch mode with your setup should get you 90+90 up front and 250 bridged for the sub.
For a short time I ran mine in 3ch mode with a pair Hertz HSK 165 components up front and a pair of g210 boston acoustics subs @2ohm off the bridged channels. I don't recommend this as it does exceed the rating of the amp, but the amp never over heated. I have since then added a mono amp to drive the subs. The only thing that I feel could (reasonably) be better is the efficiency between like 30-60% volume seems flat. By this I mean that the increase in volume between 30% (on the hu) and 60% is less proportional then from 0-30 or 60-100%.
If space is your primary deciding factor take a look at
this amp. I am not aware of another amp this small that is capable of delivering as much power reliably. The 2 possible negatives about this one are that they tend to run warm to hot depending on your setup and being a class D amp the damping is a bit lower then an A/B amp.
I just noticed that Alpine has moved away from using A/B class amps for their multi channel amps and now offers only class D. This is not a big deal for mids and highs but the lower damping may be noticed if driving subs. In any case these are good amps for the money but not audiophile class... you get what you pay for.