Howdy Dan,
Well there's plenty of 5 1/2" .45's so I guess you must be wanting the longer barrel. They just got a big shipment from Uberti and there is another shipment on the way. One of those shipments has some 44-40's, but other than that I don't know if there's any .45's. They do have a list of what is on those shipments but I won't be there again until mid next week. Your dealer could ask them if any of those are on the new shipments. And then again, it is possible that any that might show up are already backordered.
I always suggest to folks who want something that isn't in yet that they have their dealer call Cimarron and put them on the backorder list. There is no obligation and no down payment. When the item comes in, whether it is in a month or a year, the sales folks start at the top of the backorder list and call the dealer to see if the item is still wanted. If it is (they usually give the dealer a couple days to contact the customer), they charge the dealer and ship it. If not, they move on to the next person on the list. That is your best chance of getting what you want. If you find one elsewhere or change your mind, you can always say no thanks when the call comes in.
Good luck.