[Repeater-Builder] Homebrew low power Repeater

[Fred]

Hello:
I would like to build a low power 5 watt crossband repeater for 2m/440 use. I 
recall seeing this set up using 2 HT's, also 2 mobile rigs.
Has anyone built something to suit my needs, or are there kits available ?
Thank you
73 de Fred W1POP