My DM lets me create my own gizmos. i'm a thief and need suggestions.

[xzyx]

So, I'm playing a Rogue/Investigator with a huge bonus in in Knowledge (Engineering), and in Craft (Alchemy) and a blacksmith pal who wants to create gizmos and contraptions to help in my thieving. We're playing as part of a thieves guild so I have plenty of supplies too, but little gold. And it's a no-magic world, so mundanes only (low level magical itens refluffed as mundane may be possible, if unlikely). I'll talk about mechanical benefits, price, etc with him after I have the concept for the item. Can you guys think on cool devices to help with my thieving?
I have some ideas already:
-Parachute cloak
-Spring sheath knife and thieves tools
-Spring loaded crank crossbow with collapsible grappling hook
-Reverse boots that leave footprints in reverse to make me harder to track.

So yeah, not many ideas. Do you people have more?

I already have a way to break stuff easily (applied engineering investigator talent), and to climb stuff (the crank crossbow + grappling hook). And I've got a weasel for animal companion, so if he can benefit, it's cool as well. So that's covered. And I'm more interested in non-combat stuff, tough devices useful in combat would be cool as well. We're playing Pathfinder, but stuff from 3.5 would be great as well. And yeah, I already checked the complete Mcgyver handbook. It's awesome.

[phaedrusxy]

Awesome stuff from 3.5:
Torchbug paste (50 gp each, CScoundrel p120)
Splash weapon, ranged touch attack, 10' range increment. Targets in square and adjacent squares are affected as if by Faerie Fire for 1 hour. Not magical. Can be washed off as a full round action with at least 1 gallon of water.

Antitoxin
Price: 50 gp
Weight: --
(PHB)
Where else are you going to find a +5 alchemical bonus on saves for only 50 GP? Chug one of these vials when you know you're up against a creature using poison, and you've got a good chance to save yourself the cost of a neutralize poison potion or scroll. Lasts 1 hour.
Craft (Alchemy) DC: 20

Auran Mask
Price: 60 GP
Weight: --
(Complete Mage p. 134)
Provides a +5 circumstance bonus against inhaled toxins (which stacks with Antitoxin), but this is easily overshadowed by 10 minutes of water breathing. Requires less upkeep than Air Plants. For longer durations, consider a potion of water breathing for 750 GP, which lasts for 10 hours.
Craft (Alchemy) DC: 25

Lasso
Price: 1 GP
Weight: 3#
(Book of Exalted Deeds p. 34)
Exotic weapon but ranged touch attack to partially entangle a creature (-2 attack penalty, -4 Dex penalty), but unlike the net there is no size restriction. Check with your DM if the Dex penalty from multiple sources stack (net, tanglefoot, etc.).

Tangle foot bag (50 gp)

Liquid Smoke
Price: 20 gp
Weight: 1#
(Oriental Adventures p. 78)
Same price as a smokestick, but reacts with air and thus does not need to be lit. Provides concealment, blocks LOS, or a cheap theatrical effect.
Craft (Alchemy) DC: 20

Marbles (4 left)
Weight: 8# each
(Arms & Equipment Guide p. 24)
Standard action to spread. Basically a 5' x 5' square of non-magical grease. Dump them under an opponent without 5 ranks of Balance to deny his Dex bonus and make the party rogue happy.

Wick, Candle (x5, 2 SP ea.)
Price: 1 GP
Weight: --
(Arms & Equipment Guide p. 27)
Can be used anywhere you would use Twine (Dungeonscape p. 33), such as tripwires, improvised alarm systems, fishing lines, signal kites, or hang from the ceiling to detect invisible flying creatures. In addition, you can use it as a timing device: it takes 30 seconds (5 rounds) to burn 1 inch. Comes in 50' rolls.

[phaedrusxy]

I have a character who gets great use out of a pair of Boots of Spiderclimb, and I could imagine those being alchemical in nature, too.

[Solo]

Thunderstones are good, but you need to take it to the next level and ask your DM for an honest to Pelor flashbang!

[Cagemarrow]

My standard answer these days for mundane gear is lots of shapesand from the Sandstorm book, you can even craft it with your alchemy skill. Just shape it into blocks on your belt when not needed and then pull one off and make your wisdom check to make it into any tool you need.