Check out these big 10mm common cathode through-hole LEDs! The opaque epoxy package causes these LEDs to have a soft, diffuse glow.
LEDs and Illumination - SparkFun Electronics
LED - 10mm Cycling RGB (fast) - COM-11453 - SparkFun Electronics
LEDs and Illumination - SparkFun Electronics
LEDs and Illumination - SparkFun Electronics
Diffused LED - Yellow 10mm - COM-10634 - SparkFun Electronics
Diffused LED - RGB 10mm - COM-11120 - SparkFun Electronics
LED Mixed Bag - 10mm - COM-13326 - SparkFun Electronics
Enginursday: Non-Addressable RGB LEDs - News - SparkFun Electronics
Diffused LED - Red 10mm - COM-10632 - SparkFun Electronics
LED - RGB Addressable, PTH, 8mm Diffused (5 Pack) - COM-12877 - SparkFun Electronics
LED - RGB Addressable, PTH, 5mm Diffused (5 Pack) - COM-12986 - SparkFun Electronics
Diffused LED - Blue 10mm - COM-11161 - SparkFun Electronics
COM-11120 SparkFun Electronics, Optoelectronics