http://cgi.ebay.com/WILKES-GUITARS-HALF-FRETLESS-BASS_W0QQitemZ7371259003QQcategoryZ4713QQrdZ1QQcmdZViewItem ive never seen anything so intriguing
I would think that having the habit of playing between the frets, when they're there, would make it weird to have to shift positions for the other two strings; or be a 1/4-tone off...
I prefer the 1-12 fretted 13-22 fretless 23-24 fretted (for tehslaps) bass. Way more practical and useful. Well, at least cooler. The headstock on that thing's crazy too.