Marck, I would not offer my entire night's performance to anyone for any price. If your intent is to offer portions of the service or event as a keepsake, then I would be selective of what I give them. To make a recording of a wedding service is one thing, but to provide 3 hours of dinner music makes me wonder.

Also, any type of video recorder would give you some decent quality sound, with or without video. I think your cassette idea is good enough for this first try. you could attach the RCA line outs from your amp directly to the cassette to reduce room noise. Good luck.

For the record I settled on a Sony TCM-210DV. The second-closest Staples to me had it in stock, so I picked one up tonight. For about $45 it seems like a nice piece, and the AC adaptor is included. I've already tested it out recording directly from the PSR-3000. The sound quality is what I would call "perfectly mediocre". It has automatic level-limiting which basically adjusts the recording level to the sound input, so if I play loud it will take it down a notch, and if I play low it will amplify it. In effect it behaves like a compressor more or less. The recording sounds good enough to present to the client as what they asked for, but not good enough to replace my live performance. Thanks Sony, and thanks for all the advice everyone.

Well the deed is done. The tapes I gave them probably sound like horse excrement but on two days' notice (and at no extra fee) they got what they wanted. I'll probably never use the Sony for this purpose again; if I start to do weddings on a regular basis I'll invest in a Zoom H4 or the like and produce proper recordings either as a bonus or for an extra fee.