I've been fitting outboard bearings to the servos in my flap installations in the last couple of builds. It makes for a very tight servo installation with residual backlash and slop down to the absolute minimum. In fact, it is only the slight bearing backlash remaining; with very good quality servos, such as MKS, this would be absent.
I'll submit a picture of one out of one of my Wompoo's. It's difficult to take pictures of them in a new operational wing, due to access difficulties etc.
This was a very cheap DIY way of doing it. I just made up a laminate sheet and cut out the bearing supports from that. The bearing is a press fit into the little laminate block and it is glued to top and bottom skin. I similarly link both skins to my servos to avoid flexing of the skin where the servo mounts.
I've tried several bearings from several sources. Very mixed quality and availability and cost. The ones I have now are cheap and available from Banggood. A$2.32 each delivered. These are 3x8 mm and will suit the bigger metal geared servos with a 3 mm horn retaining screw. All that is then needed is a longer screw and a suitable spacer between the bearing the horn. And of course, the support block as above.

http://www.banggood.com/Wholesale-Su...1-p-58277.html

I've already posted a picture of one bearing installation on my Wompoo build thread, but here it is again: