What you're inquiring about has actually been done, many times, on a whole bunch of different boat designs. Usually by folks new to sailing, & who wan't "bulletproof" rigs. It's not as tough as many here make it sound, & 150yrs ago, it was kind of common practice.
Also I've seen a few commercial
designs where what you're proposing was done, or real close to it. And because of the extra windage, when a breeze as stiff as all of 25kts would kick up, he'd heel over 10-15 degrees in his slip.
In case you're curious, it was a Hans Christian design.
The weak points of any rig, generally speaking, are the end points of the wire; where it enters into the terminal fittings, & the various end fittings connecting things together. Such is the case even with Rod.
That's where say, 98%+ of all failures occur.
One rig design which will intrigue you, as it's kind of along the lines of what you're thinking, is the B&R rig (Bergstrom & Ridder). There's not exactly an encyclopedia of info about them out there, but the design's both unique, & has a lot going for it.
- Enough so that Hunter
, de-tuned it a bit, & put it on several lines of their boats.
In theory, it has; more performance for less weight aloft, & redundancy in rigging wires... plus a bit more tuneability in one's rig.
Look up the vessels; Route
66, Tuesday's Child (or maybe Thursday's), the Hunter
HC 50, & you'll also run across the name Warren Luhrs in conjunction with many of these. Also, there's info on such in the Dashew's book, below.
Do yourself a favor, & pick up copies of:
Brion Toss's The Rigger's Apprentice
The Dashew's Cruising Encyclopedia vol. II
<-- Get a used copy on Amazon/Ebay/Half.com for 1/2 price
If you study them well, you'll know more about rigs, rigging, & structures than 99% of the sailors afloat. Including bits on rig design, safety
factors, pro's & con's of rig types, & various materials, weight aloft, failure modes inspecting things... et all.
Not to mention sailing in general, & cruising.
They're a bit out of date when it comes to say, synthetic rigging, soft shackles, & the like. But such info is easy to pick up online. Have a look over at www.forums.sailinganarchy.com
there's LOTS of practical knowledge at the latter. And doing some perusing @ www.bethandevans.com
wouldn't hurt either, given their depth
of knowledge, & all of the sailing that they've done.
Also, Evans has done a LOT of work with some of the top riggers, & line manufacturers, to come up with KISS methods for using the modern high tech lines for all kinds of mundane uses, formerly reserved for pricey metal fittings & such alone.
PS: When it comes to doubling up on shrouds, it's not Too uncommon, to see 2 cap shrouds per side, & double lowers (fore & aft leading). As these are the 2 places, generally speaking, which get the highest side loadings on the rig. And which the rig will, without question, fail, if they do.
Look at boats designed for expeditioning, especially at the extreme ends of the spectrum, latitude wise.