Ever since I bought The Tome of Blood (a great Black Crusade supplement) I've been trying to figure out a way to translate the rules over to Deathwatch. What I'm having a problem is, is how fluid Infamy expenditure and gain is. I thought about using Renown, but you can't buy it, roll for it, and it's a lot harder to earn.

What do you guys think?

Port over the rules for weapon mods/defects from BC and assign a reknown cost to them maybe? I would make the player take the item as signature wargear first though.

You might just have it be a completely narrative thing for the crunch of them and then add the reknown cost as it feels right.

To me it almost feels like there should be two effects - 1 you need a certain amount of reknown for the watch fortress to let you wander around with said weapon, but also if long time enemies see a DW marine with that weapon it should translate to "oh **** they let him carry THAT, he must be a badass."

I've been noticing a bit of flavor difference between DW and BC. BC seems a lot more innately character driven while DW seems to have a lot of options for backgrounds for gear. So, in that vein, I devised a system where they take a weapon as their Signature Wargear at least once and that weapon will begin to accumulate "Eminence" with a base equal to the user's Renown. Eminence can be purchased like Notoriety and is accumulated much in the same way (except for relatively "better" things) that Notoriety is. The PCs can spend Eminence to fuel weapon abilities but will spend them much faster than the accumulate if they do so.