Yeah, it's not just Reason. I'm using the Alesis 10 Studio through midi via my US1800 (couple microseconds..negligible) into SSD4 through it's host, Reaper (another 5ms, still doable) then output through channels 3/4 on the US1800 and back into inputs 13/14 of the US1800 into Reason (6-7ms) and then through Reason and back out through 1/2 on the US1800 to the speakers (another 5ms)...totals about 20 ms even at lowest latency in/out.
The only other thing I can think to do, is monitor via Reaper to cut out the extra latency, and then render the tracks and import them into Reason...it's still a drag, but I might get tighter performance. Just have to hook up one set of monitors on 1/2 for Reaper's out and the other set on 3/4 to hear the song via Reason...and then comes searching for how to get them to sync.
and come to think of it, I could just export the song as a two track from Reason and play it through Reaper while tracking the drums, then render/import. Might be a lot less hassle. Getting perfect alignment is going to be a headache no matter how I do this, but I need something that will work for the situation I find myself in. Seriously wish I had room for my Pearl kit in house.

I also wish I could get Steven Slate to make an RE, or Propellerhead to open up to AAX (their one major flaw).
Still, using my real drums would entail mike placement (as well as necessitating the purchase of more mikes, which I cannot do at the present) and other hassles such as not being able to play most times of the day.
I think I'll try option 3 first...
