From the Machina J&D deck, you can take out the Junk Synchrons and Debris Dragon and replace them with the standard 6 Gadgets (2 x Red, 2 x Green and 2 x Yellow) as well as replace some spells and traps and you will get Machina Gadgets, which is really close to using 3 of the same structure deck. I just come across this Pojo 13 March 2010 Garden City Regional Report posting by Gambit01 who piloted the deck to top placing:
http://www.pojo.biz/board/showthread.php?t=819366
The thread includes his decklist, his report as well as him answering questions regarding the deck and competition. Here's my take on his Machina Gadget:
Monsters (19)
2 Red Gadget
2 Green Gadget
2 Yellow Gadget
2 Scrap Recycler
2 Machina Force
3 Machina PeaceKeeper
3 Machina Gearframe
3 Machina Fortress
Spells (13)
3 Machina Armored Unit
3 Book of Moon
2 Smashing Ground
2 Fissure
1 Heavy Storm
1 Mystical Space Typhoon
1 Limiter Removal
Traps (8)
2 Roll Out!
2 Bottomless Traphole
1 Phoenix Wing Wind Blast
1 Mirror Force
1 Torrential Tribute
1 Solemn Judgement
I intend to keep the deck size to 40. I am missing Oilman, Tragoedia, Starlight Road and the 3rd Smashing Ground. Of the missing cards, I think Starlight Road make the biggest impact as it can be game-breaking. There are no Cyber Dragons and also the choice of 3 Machina Armored Unit which is like an alternate Black Whirlwind for Machines. There are some Pojo forum posts saying that it is a slow card over at the Official Machina Discussion Thread but an interesting note is that having more than one out stacks the effect. Gambit01 should be replying to more queries over at that thread linked above so do check back there.