Hi Dan.
I had a large cabinet from Ikea for a long time.(185cm high x 18cm wide) but like yours it had very limited shelf space.Im still going to use it for 1:48 planes though, when I get around to building some, but my 1:72 stuff was swamped.
Recenctly SWMBO was hunting for a wardrobe and we visited lots of charity shops and house clearance centres. They have proved to be a good source of cheap display cabinets.
I picked this one up for £12. Its 54 x 54 cm and theres enough room for 20 1:72 aircraft in there. The front door is hinged and there are 5 shelves and a mirrored back, so the all round view of the aircraft inside is excellent.

Nige
PS,,we still havent found a wardrobe,,LOL