If you can make one and bring it to market for the right price then I'm sure there'll be a few bob in it for you...

I hate to be a damp squib but there's something else you need to take into account:

Film is thin, very thin. To make a "universal" sensor that works in all cameras you'd need to make that the same thickness, otherwise the registration distance would change and you'd lose infinity focus on all lenses.

It could well happen one day but I think we're probably some years (decades even) from seeing that sort of technology in the shops. As for price, this would make Leicas look mainstream so expect M9-esque prices to match (ie no change from £5k).

I think that's probably your problem - I searched for "Spotmatic" and went through all the results twice with no joy, then remembered it was a SP1000. I'm betting the number of folk who search for "SP1000" are probably outnumbered by those searching for "Spotmatic" by several hundred to one.

As it has no bids yet I don't think it's too late to change the title - that one magic word could bring in a flood of potential buyers...

Make that two watchers now...

The new lens looks excellent (I'd expect nothing less though) and is half a stop faster than the DA35 Limited.

Having said that I (as the owner of a DA35 Limited) don't need that half stop of speed but I would miss the Quick Shift, the built in hood and the ability to keep focussing up close until the lens is almost touching the subject.

If I was looking to buy a 35mm lens now I'd still go for the Limited, but I can see equally valid reasons (weight, cost, speed) why people with different needs to mine might go for the DA-L.

It's nice to have a choice in the 35mm arena again.

I've had nights like that before...

The 77 is, in my opinion, just right in size - neither so small as to be fiddly in use or too large to be unwieldy. In terms of dimensions and weight it's pretty much a dead ringer for the DA 35 Macro, both also sharing the same slide-out hood design.

I've never tried a DA70 but I did try a DA40 and found it too small for my fat fingers to get a comfortable grip on...

Pentax in the screw mount (Takumar) era standardised on 49mm filters; when they made the change to the K mount they unwisely decided to follow Nikon in using 52mm filters as their "regular" size - this at the same time Olympus wowed the photographic world with the OM-1 and its range of compact lenses based on a 49mm filter size. Pentax quickly tracked back and launched the smaller M series cameras and lenses based, once again, on a common 49mm filter - this run has remained unbroken up until today.

Obviously there will be certain lenses in each range that will require larger filters but I do like the way Pentax allows you to build a set of lenses with a common filter size - all those in my sig are 49mm with the exception of the DA12-24 which takes 77mm filters (another common Pentax size for the larger lenses).

I've got an M37 - M42 adapter, it's a little fiddly but it does work. Shame though, I'd have snapped your arm off for the M42 version but I'm not really interested in the earlier one.

...still worth it though...