I'd say, in my non expert opinion, that it is feasible. The main limits are storage, and availability of the hydrogen fuel.
I think diy tanks are a good solution to the storage problem. I was researching this a while ago, and one thing i saw was that you want to make sure the gas stream is of high purity (ie no oxygen) before you compress it, in order to prevent explosions May not be true/much of a problem but there is that to consider. I think if we developed an open source SLS, SLM, or EBM 3D Printer we could easily produce the tanks (in one rigid non welded piece too by that method). Another option, which is a bit more difficult is cryogenic storage. This could be a possibility if we could develop an open source cryocooler of some sort. If it is good enough for NASA it is good enough for cars, or something like that.
On the note of availibility I think the largest limit to the hydrogen economy is the lack of available filling stations for vehicles on the go. I think this could be solved by an Open Source easy to manufacture water electroliser. Then either connect that to a pressurizer, or a cryocooler setup and you are good to go. This way you can at least have a home/community level filling station if only that.
Another way of producing hydrogen, and the way that is sadly more common, is the steam reformation of hydrocarbons. This is bad when using fossil fuels, but may be something to consider if we could use bioreactor produced methane.
I will start up a construction set for this on this page.
I think hydrogen could also be used in fuel cells for electric cars or energy storage as well, (maybe even scramjet or possibly rocket engines!), so this is a technology that could help our efforts greatly.
Anyways i think this is feasible, and something that could significantly impact the world for the better.