Need help building a DIY Water Dragon viv

Tara and I went to the local fish store today to get hermits for our marine tank... figured it'd be about $10 or $12, but the bill came to $155. :O !!!! Darn expensive hermits!! We ended up coming home with a Chinese Water Dragon, a subadult. We've always admired them and have attempted to raise a WC baby in the past, to no success. This one is older and has gotten through the tricky stage in spite of living with a person who had no clue how to care for them (he was simply dropped off, cage and all, at this store).

So he is in a 20 long now, which is way inappropriate, and I need to get him into a taller viv with solid sides ASAP.

I was thinking about possibly converting a piece of old furniture into a viv-- something like an armoire or other type of "deep" cabinet.

I'd love some suggestions on how to proceed... I'll need to heat it with bulbs, provide UVA/B, ventilate it, and also make the inside water proof.

I suppose I could also build from scratch. I've never done this, though, and don't have any particular skills in it.