Those Scotts at http://www.accurate-armour.com/ should be well able to do those - I have one of their 88mm deck guns and one of the wintergarten mounted flak guns on my otw type VII. Scale is 1/35th.
88mm deck gun.
20mm AA gun.
The deck gun comes in at £25 and the AA gun at £10 - now for those of you in the US... a pound is nothing and a dollar is nothing, but it takes two of your nothings to make one of our nothings!