Thanks for the input so far guys - but just to clarify the bit about the 'stretch' - I snapped the tendon in my pinky as a kid, so sadly I have no use in the end of it now, so even with the best will in the world, I can't use it to fret a note, which is what makes the dimensions of the concert more appealing.
I only strum chords, and I can pretty much work my way around most chord shapes (or variations of, adapted to suit only having three useable fingers) - but it's a little bit easier to adapt those shapes on the smaller fretboard.
But there is no doubt about it - I LOVE the deep, more 'guitar' like tone of the tenor, so maybe my ideal uke would be a brand that tends to have a slightly smaller scale length in their tenors? Or has a slightly larger body in their concerts?
BTW - budget is going to be about $400 max - as I need to keep some budget back for a new surfboard!