Hi Sarah. The Hamster Heaven is a bit on the small side and the tubes and penthouse etc would need removing and blocking off anyway as external tubes just lead to abnormal behaviours and the hamster nesting in the tubes - plus steep sloping tubes aren't suitable for dwarf hamsters

It also seems quite an expensive price. They do much better with just inidivual tunnels at floor level - it can be cardboard or plastic, but cork logs are very popular as they add texture as well for enrichment. When that cage was used in the past, most people just didn't use any of the plastic contents and set it up from scratch - even the shelves are a bit useless! A 40 gallon breeder tank would be bigger than the Hamster Heaven.
Recommended sizes do vary in different countries (are you US or Canada I can't remember?)

But most people are going with the Uk recommended sizes which are 40" x 20" - but a 40 gallon breeder size (about 35" x 18") is also still used a lot and considered ok in the US.
If you prefer bin cages to the idea of a glass tank, then check out Home Mart - I can't put a link unfortunately as for some strange reason it won't let me access the web page because I'm in the Uk not the US - they have set their access to the site to US only it seems. There is a 160 litre sterilite bin available there I believe and some larger ones as well. However, for a bin cage you'd need to do the diy to fully mesh the top panel.
I can completely understand preferring the idea of a cage as there is no lid to worry about as with a tank or a bin cage

Unfortunately the Hamster Heaven is about as large as they go in the US. There is the Prevue cage, which is about the same size but taller. That would allow for deeper bedding though if you put cardboard round the inside bars - to help increase the depth of bedding and lower the height. It also has front access. But a 160 litre sterilite bin would be a much better size. If you can make the lid ok.
I'm slightly concerned you mentioned your cat as a reason for needing a meshed lid. Really the cat should not be able to go in the same room as the hamster. It can really stress hamsters out if they can smell a cat in close proximity. Also with a bin cage, a cat can easily pull it over onto the floor. At least a tank wouldn't budge! Is it possible to have the hamster in a room where the cat doesn't go?