I have two 22L: one (early production) with #2 collets (i.e. Hardinge 50V), the other (late production) with NMTB 50 spindle. I have never heard of any having a NMTB 40 spindle. I thought that the only VN with 40 taper spindles were the very last models.
I have not touched so far the older of my two machines, therefore I am not 100% sure that it is not a B&S 13 spindle with a very tightly planted collet adapter. However, I believe that you could get the machine with one of the three spindles: VN #2 collets, B&S 13, or NMTB 50.
Adapters: I believe that it is probably the only machine using B&S taper, therefore not too much tooling available. You might find adapters to smaller B&S taper tooling. But not much else.
You will be better off making your own adapters, one being rather popular would be for using 30 taper tooling.
If you intend to be able to remove your adapter from the spindle at a later time, it is important to use a hollow drawbar for the B&S 13 and the drawbar for the tooling resting on a shoulder of the adapter (i.e. not further pulling the adapter into the spindle while tightening the tooling).
Paolo