A cheaper way to get room noise is to just put a mic out in the room somewhere. That way you can blend in how much of the room you need to hear. I fussed all weekend with my rig, and came up with a pretty good solution that involves a single TC FX-150 as a stand mounted monitor. (My kb stand is the "X" style, so I have a small mic tube mounted on each end - one has a boom for my mic, the other holds the TC!) This is a way cool piece because it allows you to monitor several things at once, and if you need to... even send the outs of CH1 and Ch2 separately to an end destination. I send the kb into ch 1 & 2, and use the built in DI to send them out in stereo. I still monitor in mono, but I can hear my mains too.
I'll take some pictures on Tuesday and post a detailed report on it's functionality on the job.
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I will share one cool tip today:
If you're not much into the DNC controllers, like me, and you play a combination of LH bass and arranger bass ... try setting up your three buttons over the joystick like this:
1] Style bass mute
2] Style acc 1-5 mute
3] Bass & Lower Backing (this one assumes that you have your lower sound off when the arranger is playing)

Scenario 1: You're playing a tune that has an acapella break coming up, but you want your drums to continue, and chords sent to the harmonizer ... push #1&#2, continue to finger chords. Your harmonizer will change correctly without hearing the chords played. When the break is over - hit the switches again. It's also great in smaller, more intimate setting to mute all of the arranger tracks (except bass and drums) for the beginning of a song, and bring in the "band" later on, like in a chorus or last verse situation. It's a cleaner, less "canned" sound for the beginning part of the song, which, many times, is a bit simpler anyway.
Scenario 2:
You're in arranger mode with the left hand silent ... I use this exclusively to thin out the arrangements, because I play mostly full chords with my right hand, and don't want too much going on that I'm not controlling. The song ends, the rhythm stops and you want to milk the last chord while you show off vocally, or announce something of importance ... well, the kb is silent below the split point! Push #3
That gives you an instant bass note for the ending transition. You can also hit the manual bass button, but it's a further reach. You can stretch your pinky over to the DNC button while playing, sometimes.
Hope this was not too confusing, and someone can use the tip!!
(BTW - thanks for your kind words, John!)