It's weird, it's instock nearly everywhere, but on ebay, theres completed listings for just the lamp for anywhere from $90 to $120.
http://www.ebay.com/sch/i.html?_from=R40&_sacat=0&_nkw=metal%20gear%20revengeance%20lamp&rt=nc&_pppn=r1&LH_Complete=1
I caved and bought one off amazon personally.