Options for long term storage of helium? Specifically, if I wanted to purchase a large amounts of helium, what are my options for purchasing helium in a state that is suitable for long term storage?

It's my understanding that if I were to buy helium in bulk it would be shipped cold, as a liquid.  Keeping helium in liquid form for 10-20+ years would involve a lot of serious refrigeration.

Are there other reasonable options for bulk, long term storage?

This may not seem like much of a "chemistry" question but since this is used in chemical sciences, I assume this is a need that some may be aware and may have a good answer since this is an elemental material that some may use on a very common basis.
In my experience, for small quantities in laboratories helium usually comes compressed in cylinders. Except possibly in the case that you require extremely high purity, I don't see why helium couldn't be stored for long periods in this form, it would be relatively safe and would avoid the need for refrigeration.

I don't know what sort of quantities you are thinking about, but it seems that you can get big cylinders. For example the largest cyclinder size available from BOC gases, a British company, is 194.7 $m^3$ filled to a pressure of 300 $bar$ (source: BOC website).