What cab are you going to be playing through? Or do you mean that you need both a cab and a head unit for around $1K? If you don't need horribly loud volume, I REALLY dig EA's cxl-112s for fretless work. That cab is the most articulate cab out there IHMO. You can pick them up used for $350 to $400 last I checked. That cab with any good clean head will kick massive booty.
I ran a fretless J through a thunderfunk, ampeg 410 hlf combination a couple years ago that sounded phenomenal. The ampeg cab was kinda a one trick pony from what I could tell, but that trick suited my fretless J. I recall the words "chewy mids" popping into my head at that gig. My fretted 'wick didn't fare as well with that combination. If you need a cab for higher volume stuff and don't mind the cartage and lack of versatility, might want to check a used 410 hlf out. I mean, I can still remember that sound two years and around 300 gigs later.
Head wise, I personally would avoid anything overly "tubey" for fretless. That tubey tone seems to mask the natural mwah/growl from a fretless with a different tubey growl. Nothing wrong with tubey growl, I just dig the tone of the bass more than the tone of a tube. Ex: While I personally like the mesaboogie walkabout head for a tubey sound, I think it sounds like poop for fretless work. There are some used thunderfunks popping up in the classifieds now that the 750 thunderfunk is out. I am pretty much done head shopping since getting mine. The tight lows and mid punch of that head makes it my personal ideal head for fretless. A LMII would probably work as well, but the greater treble "sparkle" response of the LMII would be a detriment on fretless IMHO. Then again the LMII is no longer the flavor of the week since the shuttle seems to have taken over the hype throne. You might snag a super cheap markbass head.
All, my opinion obviously.