I thought I'd post my results to encourage others to try this wonderful format. I just returned from a three week trip around the country with it, and now I want to shoot nothing else. Very portable- it fits in a mountainsmith odyssey backpack with 4 holders and 3 lenses and feels about the same as my 4x5 outfit. I made it from mahogany to keep the camera under 10 lbs and the holders at about 12 oz each. There's die-cut film from J&C available for it- Ilford fp4+; hp5 and aslo adox/efke PL100, which are about the only films I use anyway- also the price is roughly equal to 8x10 so it isnt too exorbitant. Also, most lenses for 8x10 will cover as the diagonal for 5x12 is only 330mm. While not a true ULF the size is wonderful for contact printing and the negatives are still relatively easy to handle ( I was able to load holders on my lap in dark hotel bathrooms). I made eight holders mainly because I didnt want to have to change out the film too often but I'm really glad I did because tool setup was the most time-consuming aspect of making them. I wanted to thank Barry Wilkinson for providing some timely dimensions from his Canham 5x12 (I stole many ideas from Canham and Lotus- thanks and sorry!) and also Sandy King and Barry Young for info on making holders. I was agonizingly nervous for the past three weeks since I only had time to test 2 exposures before we left but I just got finished developing the 'normals' and everything looks good.