While I've never had an actual pretzel sandwich I did recently have a very good sandwich on a pretzel roll, from Der Pretzel Wagen
It's called the Greedo
and has ham, turkey, bacon, cheddar, and wasabi on a pretzel roll. Very filling and very tasty!
And since Der Pretzel Wagen just happened to be parked outside Triton Brewing
that day I was able to enjoy a nice microbrew with the sandwich. This was their Magnificent Amber
and while it was good it didn't cut through the sandwich well enough, so I ordered a half-pint of Railspliiter IPA
and the extra IBUs made for a better match.