Whilst technically not VESA compliant the most critical part of the VESA signaling is the deltas, not the absolute levels since pretty much all systems ultimately AC couple to the inputs. DC coupling is just not good for long cables
You can simply add a large series capacitor (47uF+) to AC couple the outputs just before the connector. This is often not implemented since all receivers will AC couple their inputs since they need to do this anyhow in order to do DC restoration by clamping the input signals.
Not sure what protection you are referring to? Do you mean for ESD or output short circuit?
TI does have a number of analog VGA buffers, e.g. http://www.ti.com/lsds/ti/amplifiers-linear/fixed-gain-products.page?paramCriteria=no#p480=3 depending on your specific requirements.
BR,
Steve