Try Gander Mtn, Fleet Farm or Cabela's. You may have one of those near you. They've probably got them on clearance if they have any left. The guide is a nice size for 2 people.
I just bought a Frabill Solo which in my opinion is better. It's a little narrower, but it's taller than the guide and I like to be able to stand up. It's listed at 67" high. I also think the seating system is better. It's modular and I'm going to buy an extra seat. That way, nothing's bolted to the sled and I've got flexibility to use with one or two seats. The seats are more comfortable and swivel. They've got a built in rod holder and drink holder (more important). The door opens left to right versus up and down. Small, but I prefer. And it props 1/2 open easier to use as a windbreak.
Just my 2 cents, but why I switched from a clam to Frabill. Good luck with your search. -cityfishin