not sure of too many compilations, but here's 3 that I have...
1. "with my little ukulele in my hand" (4CD set). mainly old stuff from 1st half of last century. BRILLIANT. trad Hawaiian, country/folk, George Formby etc, wonderful historical record too with beautiful accompanying booklet
http://www.ebay.com.au/itm/My-Littl...965303934?pt=AU_Audio_CDs&hash=item33728ef67e
2. "Square Pegs and Round Holes" (American Aspergers Assoc. benefit CD). more modern/contemporary stuff including Victoris Vox, The Barnkickers, Jim beloff, Ian Whitcomb, James Hill, Gerald Ross, John King. Sweet compo
http://www.cdbaby.com/cd/squarepegs
3. "Bosko & Honey's Ukulele Safari"...oops, just looked it up and it's sold out...but that is a great one if you can find it on ebay...more way out and bizarro left of centre stuff from all round the world..but awesome
I can recommend stacks of brilliant solo CD's by individuals...I have a pretty decent collection these days of old and new. PM me if you'd like me to send you some. My fave artists are Cliff Edwards, Lil Rev, James Hill, Azo Bell and the Old Spice Boys, Ian Whitcomb, Lyle Ritz, Rose Turtle Ertler, John King, Janet Klein, George Formby, Roy Smeck, Uni & her Ukulele, Victoria Vox etc pretty much anyone who plays the ukulele.
There is also an awesome record by a member here, 'Dr Bekken' worth checking out...
edit: if you tell us what style of music you're into we could narrow down some particular artists for you that fit in that ball park