Based on your description:

1. You're planning to add a beams spanning between two posts in an open space.

2. You mentioned there are currently no load-bearing elements directly underneath, except for one post approximately 4 feet from the wall you're building against and another at the opposite end of the space towards the foundation wall (12'6' gap).

3. Your goal is to clear-span this entire distance without any posts in between by using a beam.

However, there are some considerations:

a) Since each stud will act as an individual post carrying weight into the floor if you decide not to use traditional joists and instead span directly from one end of the space to the other (17'), additional structural support may be required. This could involve using larger beams or installing more frequently spaced joists within those 16' spans.

b) If your goal is truly just aesthetic - meaning eliminate what appears as an 'off-center' post without actually changing how much weight each piece of lumber must carry, then yes, simply adding a midspan support beam at half the distance should suffice. However, remember that this will still result in uneven distribution across those beams since every stud down their length would now also be acting like its own column.

c) Lastly, regarding your mention of LVLs (Laminated Veneer Lumber), they do offer superior strength-to-weight ratios compared to traditional lumber due mainly because all the wood fibers run parallel rather than at 90 degrees as with regular framing materials. However, their cost can sometimes outweigh benefits depending upon project requirements so it's always good practice to carefully weigh these factors before making a final decision regarding which material(s) might work best for your specific needs.

I hope this helps clarify things! Let me know if there are any other questions or concerns I haven't addressed yet.

Lvl header beam span tables