That's exactly what I did Jay. I bought a $9.95 arm lamp from Ikea and modified it. Works great with either the B1 or MD-421 but like you say, the RE-20 is a bit to heavy for the cheapie arm.... Those Luxo booms are real expensive! whew!
Nice idea, Ken. Several years ago, I used an old articulated lamp arm...very similar to the commercial spring type mic booms. For ten bucks, one could purchase a lamp at the local department store, cut the springs for heavier support, and add a mic clip. I've since purchased a commercial version as the RE-20 was a bit heavy for the homebrew boom. My Shure SM-58 with A55-M mount (courtesy of Ken) would work nicely, as this combination is not so heavy.