Sometimes I wish I could make Renoise BIGGER! Or run in something like double pixel mode. Sometimes I’m really far away from my screen and I’m like holy jeebus I am ufckn blind! But then again my face is like 7 feet from the monitor.
I know you can change the sizes in the tracker. But it doesn’t change anything in the browser so I tend not to use it as much as I just drag sounds over to the inst box.
You can change also the fonts in the skin/fonts folder (in the Renoise application folder)
There is a config.XML for the DejaVu fonts where you can change the sizes, perhaps it affects the other fonts that you can’t change in the preferences.
My sight is VERY bad, if you guys know what -25 diopters means, then you might have an idea … 
I can manage on my 22" 1680x1050 display, but for vsts and other things I often use the Win7 magnify, I have a Autohotkey script setup that lets me use ctrl+alt+mouse wheel which is very comfortable to use.
Bit overkill but it may be useful to you.
;###### Windows 7 Aero Magnifier - Compiz style bindings++++++++++++
#z::Run magnify
#IfWinExist , ahk_class MagUIClass
!^WheelUp::
Send , #{NumpadAdd}
;Send , {Esc}
Return
#IfWinExist
#IfWinExist , ahk_class MagUIClass
!^WheelDown::
Send , #{NumpadSub}
;Send , {Esc}
Return
#IfWinExist
You’ll need to get Autohotkeys to use it though.
Hope this helps you / anyone else that needs it.
There’s my answer! Get a bigger monitor. I’ve always wanted to tilt a widescreen monitor 90 degrees and run Renoise.
Long tracker is looooonng.
And thanks funky. Mag is not a bad idea but I am running XP.