While Hardy (a terrible bridge writer imo) may have written this up, my first recollection of seeing this sort of hand type being discussed was in the MSC in the Bridge World: not surprising, since the whole idea of the MSC (at least in the late 1970's to the 1990's) was to create hands that fell in the seams of BW Standard, a method fairly close to mainstream 2/1 as it was then played (well, earlier versions were closer to SA than to 2/1, but that evolved).
The notion, as I recall, was that when one had no call that actually 'fit', one should try to use the call that was the least distortion, and that partner should realize (even without you breaking tempo
![:P](http://www.bridgebase.com/forums/public/style_emoticons/default/tongue.gif)
Here, 2♥ showing 3 is simply too valuable, imo, to use as the least distortion bid. Not only does it suggest (show) 3 hearts, but it also shows (suggests) very short diamonds, and that may cause too big an issue, should partner, for example, hold a good hand with xxx in diamonds.
So if we accept that notion, and I can see why some might disagree, then the next cheapest candidate is 2♠. I think this has to be correct because it maximizes bidding space: it is far, far easier to work things out after 2♠ than it is after, say, 3♣. What if partner was forcing based on clubs? Over 3♣ he has to bid 4♣, which we can't possibly be happy to see, with xxxxx in our trump suit, having already promised 5 with our 1♠ call.
2N is a possibility, as noted by Timo for one. I don't have an issue with playing 3N with xx opposite xxx when we have 9 winners on the side and no better game, but I really don't like playing 3N with xx opposite xx or with having a lead come through partner's Kx(x) at trick one.
2♠ is no panacea, but I think that bridge logic dictates that in ambiguous situations, this type of call has to be taken cautiously by partner. Partner shouldn't insist on spades without 4 of them.