Hey guys, cheers for the responses ^^
I did of course consider the idea of having the usual bottom copper, for SMT, with through-hole on the top. I guess the fact I'm hesistant to do that is more a question of aestetics, gotta love a PCB covered in little SMT chips.
Thankfully eagle can sort out that easily without problems, just mirror the SMT parts and they go on the bottom side. Thats a lot safer than designing it with topcopper and trying to work out for yourself any inversion problems.
Good call on the flex cables! A second board for actual 'headers' could always be atteched to the other board.
Mikebits: Agreed, they are fairly mechanically stable, and I would happily use them but maybe I'm missing something..tried RS AND farnell/newark (I'm in the UK so digikey is out for small orders) and I can only find a handful of them, plus they are ridiculously expensive, where-as 2x40 pin headers can be had from ebay for just a few cents, I literally have hundreds of them.
3V0, again, agreed, when parts have easy access to top side and bottom side, like DIP chips, they make vias. I've no problems with wires made with a bit of wire, but using a part as the vias themselves would make it neater.
As an FYI, the three idea's I'm going with are the following :
1) Pushing the plastic carrier so it is halfway up the pins, placing the hdeare in the holes with matrix board underneath to hold it, then hand soldering the pins on the topside. Then pushing the plastic carrier back down, and soldering the bottom.....like the DIP chips, these will also act as vias.
2) Partitioning a design into two parts. First contains the 'brains' like micro's and CPLDs/FPGAs as a 'header board'. With pinheaders pointing down, and the SMT parts on top. This can then be plugged into female headers mounted on the base board. Advantage of that is you can reuse the header boards for different carrier boards! In effect, as we are doing is use two boards for double sided....one as top copper, and one as bottom copper, with the headers acting a 'via's. This would especially be handy for PQFP208. (yes, some projects I have use chips with lots of pins, FPGA's, DRAM, etc..)
3) Not worth the hassle but purely as an academic approach, making my own copper bails for easily plating holes. I've spoken to a chemistry friend about plating copper onto tin solder (RoHS) using 'available' chemicals, and I reckon it could be done.
The 'copperset' system is no longer being made, and the bails are 24UKP for 500. Given that even with small amounts of chemicals I could plate maybe a hundred metres of solder, if I need loads of bails, making them en mass isn't tough.
I'm always up for 'true DIY', not like those makezine amateurs
But chances are I'll fail miserably.
Thanks for the help guys, I'll let you know which method proves to be the best. Again, this is really only for complicated DS boards, that in fact would probably be cheaper the get professionally made up, but hey, its a challenge, plus I'm a cheapskate, if it costs more than 30 quid, I'm not doing it.
Blueteeth