Ikaheimo wrote:
I can't really make anything I can sell on the AH, as only other engineers can use it - and they can usually make it already!
Look again.
First, you can make a number of items which are used in quests. For example Advanced Target Dummy is used in Gizmo for Warug, Gyrochronatom is used in Gyro... What? and Delicate Arcanite Converter is used in The Ectoplasmic Distiller. In my experience (your server may differ) the Gyrochronatom is a steady seller as it's for a levelling quest. The DAC is probably hard to sell today, but a while back you could make 20 gold just buying the mats off the AH and selling the DAC to people working on the tier 0.5 upgrade quest. Thorium Widget deserves a special mention - not only is it used for repeatable Darkmoon Faire hand-ins (and thus a great seller every time the Faire event is active) but it's also a key component for Dire Maul Tribute runs (so steady demand from non-engineers).
Second, not all engineers have access to uncommon engineering schematics. Most notably players may take Engineering for PvP and want Hyper-Radiant Flame Reflector and Ultra-Flash Shadow Reflector right away without the hassle of farming Stratholme and UBRS for schematic drops. There are also lower level Flame Deflector, Ice Deflector and Discombobulator Ray which can be surprisingly useful and as consumables are good for repeat business (whereas Reflectors are a single high value sale per customer). The Major Recombobulator is popular with some in group PvP as it removes Polymorph and again not everybody wants to farm Dire Maul for the schematics.
Third, don't overlook the profit potential in selling components for engineering. Probably the most popular option here is Fused Wiring which sells for around 5g and can be looted from expired Target Dummies.
Finally you may want to look at vanity pets and 'fun' items. Specifically Mechanical Squirrel and Steam Tonk Controller sell quite well and are easily marketed by simply using them in busy areas. Quite a few people are collectors and want to have every pet available. Again these items do not require Engineering to use.