I have the large labyrinth house for our Syrian
It's huge though - your cage needsto big enough for it! I have the one with the lift off dish on top - saves taking the whole roof off each time. He does love it though. He nests in the front left partition and used the toilet in the middle back partition (which was where I put the litter tray). I've now had to move the toilet to the right partition - and he uses it there, because he wanted the back middle one for an enormous hoard.
https://www.rodipet.co.uk/houses/rod...erracotta.html
If you just want a house with a lift off roof, and not with a litter tray inside (I think you mentioned your hammy uses a litter tray in the corner of the cage, then this one is a good size. Far too small for a guinea pig - slightly smaller than the two room house linked above. It fits together like a jigsaw- no nails. The door is large though so it works best with a bendy bridge tunnel over the door.
https://www.amazon.co.uk/Ferplast-Gu...VA8WR7T9XN59E1
As they're all wood, you would need to paint them with plasti kote(pet safe) water based enamel paint so they're wipe clean in case of accidents/soiling.
These are popular too and not so huge
https://www.rodipet.co.uk/houses/rod...t-rodents.html