I had a look at what he already had on. Bish is wearing Absolution which is priest T6 and generally dark overall. Me thinks he forgot to mog his belt..."I'd like something a bit more white."
The simple solution is to wear the T6 recolour from Black Temple.
This is a popular priest look. The helm and robes are recoloured T6 (Cowl of Benevolence and Garments of Temperance) with Mantle of the Avatar. Soulclolth gloves are nice for that peek of yellow from the sleeves (further up they have differing colours) and I used the Replica Virtuous sandals that you can get from Darkmoon Faire. I used Cord of the Slain Champion (397 version) which actually looks quite nice - might be hard to get in this current climate (as we'd have to do Normal Zon'ozz to get it) but I think it looks good witht he rest of this set. Bish already has Staff of Immaculate Recovery so he would be find if he could get all these pieces. I think a good substitute for a helm would be Valorous circle of Faith, which gives you a little halo.
I thought I'd try to whip up a more classic look for him, using the Replica Virtuous set you can buy from Darkmoon Faire.
Not sure if it's a little too candy yellow. I continued with the Soulcloth Gloves as the yellow goes nicely I think. I think the belt I chose was a bit too dark yellow, the belt Bish is using now with his current would be a good match I think.
Anyway, I hope he liked my selection choices for him. A little cookie cutter perhaps, but he did want something more classically white and priestly, using that cowl.