2. I think you have a good idea, and I would not have any problem setting up something like this. You have made me rethink my hosting options, I am thinking about offering an "automatic" service and a "diy" service to cater to both crowds. Automatic service I do everything for you, DIY service you pick your own pool, configure the miners. I can give access via ssh or whatever you prefer. I have seen a pi working with 50 Gridseeds.. you are right, the limitation is the amount of USB hubs you can chain together. The only thing about doing a diy service is I will have to bill you for the hosting fees and can't just take them out automatically. I don't really have a problem with this, just so you know. I think I would give someone up to 1-2 late on their hosting fee before taking of their units and mining the hosting fees.
Alright! I am in for a full controller block whatever that happens to be.
I think the easiest way to handle payment would be just require upfront payment for a term of several months (3 is probably a good number, since after that who knows what difficulties and feasibility will be on scrypt).
Also, while I am getting everything I asked for I might as well add a few other nice-to-haves, but I am "in" for the self-managed block either way.
(1) a bulk shipping or at least a self pickup option for someone who has a lot of units at the end of the hosting term... at $20/unit returning 30 units would be over $600 which seems excessive.
(2) just like with self-storage, at the end of the hosting term as an alternative to renewal or shipping back units, sell the units on ebay (possibly with the automatic hosting units), keeping a decent fee for yourself and remitting remainder (probably better than shipping back, especially if you have many units from multiple customers).
(3) option to ship my pre-existing units to you to add to my self-managed hosted farm (I realize this would have to include a setup fee to deal with the controller, hub, power supplies, etc. that you are already incorporating in the price of the GB units).
(4) option to power units sufficiently to mine BOTH BTC and Scrypt.. I have experimented with this and found that it is actually more profitable at times, especially with alt-coins recent drops relative to BTC .. I am working on a cgminer code that will autoselect BTC, Scrypt or both (don't hold your breath though, its really complicated) and would like to use this. It would significantly increase power required so obviously would be more $$.