Mark,
We've been kicking this 'tall drivers' thing about in a jokey way recently see the :
Re: Door Mirrors - Round or Rectangular? thread and some of the discussions there.
I'm only a 6'3" short*rse and I don't have any real problem.
I have dropped the seat in my 4/4 by removing the blocks under the runners This wasn't a leg room thing, merely to decrease wind buffeting over the top of the screen, although it has, of course, improved headroom with the hood up which is a useful because my part of the world can be pretty wet at times too.
If you do want re-assurance you might want to take a look at this:
http://www.morgans4sale.co.uk/md54fram.htm and click on 'Roadster'
The guys in the photo are Mike and Ben Duncan and as other people on this site will testify they are both about 6.5" and manage perfectly well.
I don't know where you're located but if you are anywhere near the Midlands, go along to their place ( Hartlebury, nr Worcester/Kidderminster) and get some re-assurance
Just to clarify, my only link with Mike and Ben is as a satisfied customer. I'm sure most other dealers would be similarly helpful ( if not as tall!)
Regards
G
PS . On a first drive, you might find the closeness of the pedals more off-putting than anything else. Don't worry, it soon becomes natural ( ish)