BulbConnection.com - $8.19 Wagner 4049WAG 4049 Replacement Lamp
you need the housing first tho.
But, one of my 150's burned out on me, KC sent me a new one. That one burned out too... While I was putting it in the box to send it back to KC for replacement I took note of the info on the back of the bulb: Wagner 4049
the site I listed above sells the EXACT same bulb - 150Watt for the KC Hilites for $8 each.
So if you have 130's and want 150's, now you can get 150's. just with no warranty.