Coker vs 28" semcycle/DM or what ?

I’m looking to get a new Uke before I head back to Sydney in a few months, and I’d appreciate a bit o’ advice…

At the moment I’m tossing up between the following, but I’m ready for any other suggestions.

a 28" Semcycle,
or a coker
or a 28" DM from England

I’m 6’7" tall, ~ 205 pounds.

From what I’ve read here, regardless what I get, it’ll be with a KH seat for sure…

I will spend whatever I need to, to get something suitable - but the $600 43" hard-wheel is way way too much…

I already have a great stupidly little 14" Schwinn and a 20" DM which have both served me well for a few years, but I’m after something a little more in keeping with my size, and with which to go a little faster.

On the whole I like mild trail rides - nothing extreme - and if possible I’d love to cruise with the bikes in Critical Mass as well…

Is a Coker built just for the road ? - would it be too unwieldy on easy trails ?
How much faster is a coker than a 28" - and would getting different pedals balance it all out ?

Thanks in advance for whatever advice comes my way.

 Tall Dave