Turret head for benchtop CNC mill

Hello all--Would like to bounce an idea if it's not too far "off".
Have been thinking about designing and building a turret head (tool
changer) retrofit for Sherline/Maxnc size mills similar to that found
on the "Burgmaster" type machining centers. This would have to be a
miniaturized version with maybe six spindles and a turret housing
maybe 4" across and 2" or less in thickness. Would probably do manual
indexing with the spindle drive stopped and a shot pin locater to
assure accurate position. I envision a small spur or helical gear on
each spindle exposed on the back of the turret to mesh with another
shaft driven (from above)gear only when the spindle is in operating
position.
Most of the tools used on these machines are small endmills up to
3/8" diameter so the miniature spindles would probably be set screw
endmill holders with a couple having small jacobs type chucks.
Any design ideas anyone could help me with would be appreciated.
It's going to be difficult getting all these spindles packaged in
such a small envelope.
Thanks
Nelson