electronic speedometer

Been a while since I've been on here, got the 54 F100 goin' with the Isuzu 4 banger diesel, what a blast to drive- plus, as near as I can figger in my head, it's getting at least 20 mpg. I can't be any more accurate about the true mileage, since I don't have a speedo with odometer. I tried an Aurora Instruments electronic speedo with hall effect switch, a programmable device, which worked kinda not at all- my advice, stay a long way away from that brand. Not only was the product junk, but the product support was nonexistent, and the refund policies required an act of god and a Philadelphia lawyer to expedite. Finally got my refund (less 20% restock since I decided to send it back- it didn't work because of my fault?) and went down to radioshack, where I could physically lay my hands on a GPS, and I had some recourse if it didn't work- I could take it back and take it up with a real person. At least now I have a speedometer. If anyone has suggestions on reputable suppliers for an electronic speedo and the correct pickup sensor to run it, I would be willing to listen. But I am starting to get a little (or a lot) gunshy of internet sales for automotive components- they are quick to take your money, but horribly slow to acknowledge you may have a problem with the product.... and, oh, you want customer service? Helen Waite is our customer service manager.... if you want customer service, go to Helen Waite. The same people run our government- whoops, did I say something wrong? Enjoy the last 2 months of prosperity, after early November it will tank again. Here in NY they have been fixin roads to beat the band, thats the last construction we'll see or be able to afford for the next 10 years or so. Oh yeah, on topic, need a speedo and sender- any suggestions? Thanks.