can someone make/market a minimal tensioner?

This is an idea after reading stuff here and from experience-

I don't like the kit tensioners- they are big heavy and stupid and generally people are placing them to displace all sorts of chain length pointlessly-

after all, what's usually needed is only to displace less than a chain link length on ONE chain or the other

I have built using multi-speed derailleurs, and the derailleur takes up the pedal chain slack- I just set the motor chain where it tensions- on horizontal dropouts

Now I'm doing a single speed freewheel- and want to set the motor chain first- isn't that more important?

so anyway- what I'd like is something that hangs under the pedal chainstay- just enough to push that chain tense enough- if I need it- cause I'm still not sure i will.

the photo below is just a coaster brake bracket with a pulley wheel- the pulley would not clear the stay- but if it were on a simple slider= not long in length- I could adjust and tighten it.

the top of the bracket could be like a generator light clamp- solid with a set screw to hold it laterally- that would be much less involved than a kit tensioner- and weigh less.

just a thought- any designers or machine shop takers?

That one above seems to just be at a compromised angle- wouldn't it be stronger just dropping verticly from the stay?- it looks like a little leverage on a long handled angle would push that one up-

no, it's not a replacement for a derailleur- its just a minimal tensioner to adjust the pedal chain after setting the motor chain WITHOUT one.

here's a comercial job I found on ebay- for a mountain bike I think- and it does fit on a deraileur hanger- but pricey too at over 18 dollars.

Single Speed Chain Tensioner Rigid Fixed 200-003 - eBay (item 220461572308 end time Apr-29-10 13:38:41 PDT)