I have taken the first step in building a cube for unlimited drafting.
My collection is dominated by Theros thanks to the weekly drafts so it may start of as just a Theros cube which would be pretty dull since that would just be like a regular draft but without the chance of opening cool cards to keep.
I am a few rares/mythics of a full set though and really want to use my Thoughtseizes elsewhere and I am not sure how comfortable I would just letting random people use my cube if it has cards in it that are expensive and important to me. A Theros cube without the big money cards ... boring!
There is an excellent series on Brainstorm Brewery about building a cube for under $200 (it's too small for 8 players though) which might be my go to guide. There are some really interesting and powerful cards in that cube but nothing over a few dollars. Cards like Balance and Control Magic are really cheap and ridiculous.
My other idea is to perhaps aim for a modern masters based cube. That was the most cube like set I have played and largely doable over time. If I had my old pre Korea collection (since sold) I probably could have built that already. If they confirmed Modern masters 2 was coming and there would be a decent amount of stock then I would be all over it.
I will see how far I can get with the cards I own and a bit of trading but an order to Card Kingdom may be on the cards when i get back from Australia and have my job situation settled.