I tinkered a bit with several browsers in some x86 virtual machines and came to the following conclusions (so far):

Ubuntu Phone's webbrowser-app [1]:
+ UI works mostly fine on a 800x480 desktop
+ autohiding url bar is easily accessible by dragging it up from the lower screen edge
- uses experimental QML api
- needs multitouch to zoom (pinch to zoom)
- no tabs, no way to open links in new windows, therefore strictly linear browsing
- no support for HTML 5

KDE plasma active's webbrowser [2]:
+ seems to work well on touchscreens (from what I can tell without having one)
- UI needs too much space to be useful on small displays
- depends on patched KDE libs, therefore incompatible with Debian (unless one is willing to replace major parts of Debians KDE)
- huge list of dependencies (when installing only the browser with its depends the list doesn't seem too long, but although the browser runs it only displays a black box instead of websites - installing the whole plasma-active DE fixes this but pulls much more dependencies, maybe 1GB)
- needs multitouch to zoom (pinch to zoom)

Chromium:
+ can be made to act mostly like a mobile browser by adjusting the agent string and enabling "Enable touch events" in about:flags (which enables drag page scrolling).
- url bar and tab bar to small and apparently no way to change that (this is a mayor show stopper on tiny displays)

Firefox:
+ can be made pretty much compatible with small touch screens by using the following addons (maybe there are better ones):
# Hide Tabbar (becomes visible by sliding over the region where it should be or pressing a hotkey - camera button?)
# Hide Navigation Bar (becomes visible by pressing a hotkey - camera button?)
# Big Buttons (bigger tool bar buttons - only one size available)
# Grab and Drag (scrolling)
# User Agent Switcher (comes with an "iPhone 3" setting)
# Make Address Bar Font Size Bigger (does what it says, unfortunately it doesn't increase the url bar height and places an icon in the bar that can ot be removed permanently)
# not an addon but setting this in userChrome.css increases the tab bar height so it can be used without a stylus:
- the result still looks crude (might be adressed by better choice of addons)
- when Hide Tabbar and Hide Navigation Bar use the same hotkey they sometimes don't respond to it at the same time
- url bar and tab close buttons still too small


[1] http://packages.ubuntu.com/trusty/webbrowser-app
[2] http://packages.ubuntu.com/trusty/pl...ive-webbrowser