R-44 stock is pretty good sounding, but the Oade ACM at $915 is really nice sounding to my ears. As stated, that's pretty dang close to $1k and you're not any lower than that if you have busman mod to a stock unit. So, on the basis of your post, I'll rule this out and conclude that I agree with you that if you can't get much uner $1k. However, that doesn't mean that 4 channel is out. (BTW, you are aware that there is a stock R-4 in the YS right now for I think $600 or so?? Don't forget that a bus mod on 4 channels is I think 2X$175 on the R-4...not sure about the R-44.)
You still have the option to keep your UA-5>JB3 for situations where you can get a board patch. In the meantime, buy the stock 660 for the cheapest you can and run the UA-5 lne-in into the 660. Obviously, this doesn't decrease the bag size, but it does ease cash flow problems. Once you've got an extra $175, send the 660 off to Chris for his mod. Then you can take the 660 out for those nights when you know a board patch isn't available, but take it all when you can do 4-channels.
Don't be too put off by the fact that you'd need to make ajustments in post to synch the two sources. It's easy to do if you have the right software (I use Audition)...just adds another step to the mastering process, but it's not like it takes more than an hour or two.
Incidently, the busman mod on the 660 is really excellent ++ sounding.