You had the right idea, Some suppliers are better than others.
or 20 bucks (about) you can get ECO-LED led's at many RV stores including Camping World as I recall, these I can attest are good and bright (I get the Cool White ones) but they are also expensive.
Several E-bay suppliers ship from China.. Some are great, some good, Some crap, I've gotten good and crap. I can live with good.
I do not use the lamp you use.. but this is the "Good" one, it is a "Warm White" and as I said, I would rather have Cool White
http://www.ebay.com/itm/10X-Warm-White-1156-BA15S-18-SMD-5050-Turn-Signal-Backup-Reverse-LED-Light-bulbs-/201077744627?pt=Motors_Car_Truck_Parts_Accessories&vxp=mtr&hash=item2ed12ae3f3