Hi,
I think is better if you wait and save money for a second-hand GV-1 finder.
This is my experience on this:
1- first, I try to use a Canon 28 finder (for Canon RF cameras) with manual parallax correction, black: I take it on E-Bay, from USA and spend about 80 euros for the auction, postal service, custom duty & VAT (a lot!). Unlucky with it, the area of the view was to much narrow (I wear glasses....), GRD is in 4/3 and there was a lot af things unexpected in the pics......the only way to get sharp framing was to use the GRD III in 1/1....in a winter chilly day my hands was almost frozen and it fall on the ground: the front lens (two elements glued togheter) get a bad crank and now rest on the shelf...:bang:
2- try to buy the GV-1 used on E-Bay...I find one in England for about 75 Euros but my bid was to low and I missed it for few pence.....
😡
3- a member of italian "Leicapassion" forum solded his Epson RD-1 and have one of those GV-1 finder he used for 21 mm lens on film and on digital (the GV-1 finder is both for 21 & 28 frame).....selling the RD-1 he didn't need it any more so I take it for 75 Euros.
The finder is good, a lot! It's sharp and contrasty and the view match the GRD sensor almost perfectly....I think is built by Voigtlaender/Cosina, because I own the 15 CV finder for the Super-Wide Heliar and they resemble each other a lot.
The Ricoh GV-1 finder is slightly adjusted on the right side of the camera top, so the flash-light can easily pop-up.
They, both, are bright and confortable even for my glasses.....
I must tell You.....in real life 1 Euro worth the same of 1 Dollar, even if the excange is 1.4 dollars for 1 euro (I mean You, in Europe, can buy the same for 1 Euro You can buy in USA for 1 Dollar) so I think You can find the finder second-hand for the same 75 Dollars I spend in Euro....
4- the chapest way to build a finder is to use (and destroy) a "disposable-camera":
http://www.flickr.com/groups/analogica/discuss/72157621951618618/?search=mirino
http://www.ragarecords.com/photo/diy_viewfinder.html
http://www.flickr.com/photos/wt-gr/sets/72157619378706956/detail/
The second link is in english.....the first in italian, but if You follow those links there You will find some cheap old P&S cameras that could fit....
PS: I'm sorry for my terrible english, but I learn it at school......