My beer line length is as-supplied. I think some of the foaming issue is because of the 'hot' part of the beer line that goes up through the font, and the initial temperature of the tap itself. For example if I'm pouring 2 half-litres of a German Pils at 4 degrees, when there's a mate around, the first glass will foam excessively, then the second glass is usually spot on. I keep my pressure at around 80 metric thingos (not the PSI) - (KPA????) - what usually helps is to pour off a 'nip' into a spare chilled glass first, to clear its throat, then proceed to pour the main glasses.
If I'm having a session - which is usually the case - I tip the nip back into my glass towards the end and it doesn't detract from the beer.
Edit: hence the popularity of frozen fonts, if you are rich or a fridge mechanic or rocket scientist
Second edit: Also I read here last year that someone was experimenting with using a computer fan to blow cold air constantly up into the font tower, but can't remember reading whether he succeeded or not.
