I'm the author of lnav and had never heard of logviewplus before, thanks for mentioning it. It looks like we've independently arrived at a very similar feature set, that's pretty neat. I will now shamelessly steal some of your ideas :)
It looks like you have done a great job with lnav - it's impressive. I know how much work has gone into LogViewPlus and you must have made a similar commitment. I thought I was the only one crazy enough to want to solve this problem. :-)
I've been using https://glogg.bonnefon.org/. The mark / matches feature is really handy. However there are a few bugs with highlighting and it hasn't been updated in a while. Will have to check this out!
Glogg is a great tool. We take a bit of a different approach in that we parse the log file. This enables some more in-depth features such as SQL reporting. We also support remote file access (for example, SFTP).
Let me know if you have any questions or feedback. You can reach me on the contact page of the site.
As things currently stand - hard. LogViewPlus is written in .Net using WinForms, so it is heavily tied to Windows. However, Microsoft is evolving. The bulk of the code can now be made to be cross-platform easily, but the front-end remains a problem.
I would love to do a Linux port as soon as there is a viable cross-platform GUI technology with strong 3rd party vendor support. The controls in LogViewPlus are very rich.