[Oreocookie]

I love all your creative ideas, and I'm a great fan of DIY projects for hamsters. If you have children it's a great way to spend time with them and encourage their creativity. And if you buy only pre-fabricated hamster items, it can get very expensive quickly.
I especially love all things from toilet or towel rolls, egg and muesli boxes etc. And I have made great labyrinth houses with different chambers from shoe boxes as well. They are extremely practical if they come with lids. You can make side entrances as well as top entrances. You can remove the lid in order to check on your hammie without destroying the nests. And if the house gets too soiled or shredded, you just make a replacement☺ My hammies always moved into these DIY houses and made their homes in it. So, it's obviously very appealing to their natural instincts.
If you buy pre-fabricated multi-chamber houses from pet companies you have to pay stiff prices. I think that the only item where you should really splurge is a high quality wheel of an adequate size which runs without too much noise. So, it's good for the health of your hammie and yourself.
I also love DIY cages because I'm not very satisfied with the commercial cages. They are often way too small and not very well designed. And the better ones are very expensive.
I found IKEA to be a treasure trove for creative pet owners. Is IKEA easy to find in the UK? They are everywhere in Germany. And one of the most popular cages for dwarf hamsters can be made from the IKEA-Detolf glass cabinet. For Syriens the Detolf is a bit too low, though, and one has to increase the height and/or construct a lid, which makes the project a bit more complicated. In Germany the Detolf is so popular that googling "Detolf" brings you to hamster forums more often than to IKEA. IKEA should really offer a tweaked version without shelves and a lid instead of a glass door☺ I'm sure that there are a few examples of creative Detolf-terrariums at this site here, too. What I like especially about the Detolf besides it's benefits for the hammie: it looks very modern and stylish. It's a great piece of furniture if placed on a long sideboard.
Where I live it's easy to get hold of a used Detolf cabinet for great prices. This it might be different in the UK , though. But the creative use of IKEA products has made the lives of many hamsters and their owners a lot happier.

Connecting multiple big empty cartons from parcels with tubes for posters or paper towel rolls is also a great way to construct fairly quickly a big play pen or free-run space, which can be easily de-assembled and stored. The hammie has to be supervised, though, since some may chew their way out. And my Winterwhite once escaped by climbing on an egg box in the play pen which was placed too close to one side and then jumped over the divide. I have also heard that some intelligent hammies use their digging material for constructing ramps! They push all the available material into one corner and then climb out easily!