You would need to avoid anything two storey with two hamsters because they can cause each hamster to choose its own territory, leading to fighting.
If you want a fish tank type cage, there are usually used aquariums available on Ebay, Gumtree, and Facebook marketplace.
There is also the Kerry terrarium, which at 75x45cm might be a little small for two. There are the Duna cages which are a tank style cage, but plastic, so easily portable. The Duna Multy is about the same size as the Kerry terrarium but feels much bigger for some reason (I have both), and the Duna Multy Maxi is about 100cm long. There is also the Marrakesh terrarium, which is a lovely looking cage and 96cm long, but very expensive.
Kerry:
https://www.zooplus.co.uk/shop/small...r_cages/219419
Marrakesh:
https://www.zooplus.co.uk/shop/small...es_wood/437277
Duna Multy:
https://www.portonaquapet.co.uk/shop...a-Multy-M36261
Duna Multy Maxi:
https://www.portonaquapet.co.uk/shop...a-Multy-M58956