event macro 37 0 is the equivalent of "fast weapon switch", unfortunately there's no #lweaponID that you can set so EUO would use it during the event macro.
It's entirely possible that the information is in the data stream and client accessible. To get it implemented in EUO you would have to post something on EUO forums requesting it, and see if Cheffe responds. He's been fairly active on the forums lately, so there's a chance he might comment.
And yes, long desired function. Using drag/drop for arming has sucked. If EUO had #lweaponID you could easily set it and have multiple weapons available to swap out with "fast weapon switch" speed.