Not _that_ portable, but my alltime favorite:

I wish my K4 would have a rom slot to add new waveforms...

Got your K4 used? I got 2 of them. One was new and the other in very good condition. No trouble with the keybeds...

I'd prefer the K4 (with nice filters). I paid 100 Euro for mine (very good condition).

http://www.vintagesynth.com/kawai/kawaik4.php

I like my K4. It has nice filters.

Hmmh...Kawai K4 has everything except the knobs...just a value slider...otherwise it's a great synth in my eyes...got mine for Euro 100,- and didn't regret it so far...

I like most of the sounds here:

An old Elka? X109, X19T is even portable.

I thought the K4 has all the K1 waveforms plus filters, so it should create all the K1 sounds with some programming? I've seen it for Euro 69,- and paid 100,- for mine, so is it worth to go for the K1?

I 2nd the K4. Love the strings.

Kawai K4 (bought new) was my 2nd synth after a Korg Polysix (bought it 2nd hand), that drove me nuts, since one of the key contacts or switches were always failing, when I wanted to play it. I disassembled it a bazillion times, but when it had been lying in the corner for a few days, another contact...

The space organ! Elka X707/705

(which had quite some cool synth sounds)

http://matrixsynth.blogspot.com/2005/08 ... -ebay.html