I'm waiting to buy a 2011 Lapierre Froggy but am a bit unsure of what size to buy…

I'm 6'1" tall.

I had a demo ride on a 43cm Froggy (smaller of two sizes) bike, and it's top tube length was the same as my Large sized Ironhorse (6 point 4). It suited me fine but Lapierre recommend me buying the larger 48cm bike. Although they didn't have one for me to demo on that day.

The 48cm frame seems quite a jump and I wouldn't want to loose any of its playfulness. If you've got one can you help me out by recommending a size. I really don't like feeling stretched out on a bike. Thanks

This may not be much help – but I have a S/M Froggy, I'm 5ft 9in and if I was any taller I think I would want the M/L. Especially if I was over 6ft like you.