Hi all!
Thanks for help!
I made the changes, and I hope them please you all. It was easier than I thought, because I worked hard last 3 weeks, and the board connections are in my head.
All pinheaders (except ICSP) are on the same place of SSS, and the ICSP pinheader is now at [2560, 1100] position, making it compatible (I hope) with all other arduino boards, except, of course, the actual SSS.
The power pinhead has more 2 pins, like diecimilia: Reset and another (which is used for 3,3v in diecimilia). 3,3v is not used, since SSS has only 5v. This makes it compatible with Diecimilia reset pin, right Mellis? I'm asking because I really don't know.
There are now 4 jumpers (more than 3, but still less than 6). All 4 are GND or 5v.
The wires have 0.6 millimeters, and spacing is 0.67 millimeters.
No wires between pads.
Only 3 wires under Atmega.
Larger pads (comparing to actual SSS)
Components still have the same orientation (diodes, capacitors and transistors), to reduce errors on mounting.
Schematic changes are: Switch connections (no eletrical modification); changed power pinhead from 4 to 6 pin (like diecimilia); power led 3 to 5mm.
The board has the length increased in 4 millimeters, and the IC 2 (7805) is inverted now, and can be layed down to the opposite side of actual SSS board.
I'll wait for comments and sugestions before making a prototype and publishing documentation, since I could make some mistakes again. 
I hope this would become a new standard for the Serial Single Sided Arduino.
