OK. I got one. A Roland AX7, I mean!
I saw it in a local music shop, second hand and in excellent condition so...I couldn't help but think it was meant to be, after giggling over them for several years.
Daft gimmick etc, I know, I know but it was there in front of me, crying "buy me!"
A few years ago I sold a Roland sound module and am kicking myself now as I think I could have used that with the keytar, I think. I can plug it through my keyboard but any (helpful!) suggestions of sound module type thingies I could look for on ebay etc? Of course, I don't want to spend loads, is it too much to expect to be able to get something for £50 ish? I don't know, just thought some of your techno keyboard experts may know!
It would mean I could sometimes just take the keytar to a jam night situation rather than thinking I had to take my piano or keyboard. I just want to be able to use it easily at times, without having to have a laptop set up, which is what one music shop said I would need to do.

I am not very interested in getting too involved in the technical side, more just some way of jamming along for fun with a few reasonable voices, without having to cart too much with me.