Build your own leaders with a section of T11 tied in between the butt and tippet.

If it were me, I would get a 3wt rod then get some WF3I line and skip the 1 and 2wt for such application.

Laguna Lake,

From a 3-weight on up, there are many alternatives. When one gets to a 1-weight or below, the choices decrease sharply, especially when one feels that a tapered line is an absolute necessity. However, if you can settle for a level line and use come creativity, there are more alternatives.

A while back there was a thread in the "Frugal fly fisherman" section called "An artificial silk line for a few bucks". Let's try this link: viewtopic.php?f=90&t=9353

I personally have been using twisted nylon lines for a couple of years. After being coated with two or three coats of spar varnish, they function like intermediate lines in that they float when dressed and sink slowly with no dressing or when the dressing wears off. Some people have also used braided backing in the same way, but I don't know how well it sinks or floats.

Good luck with your quest! Please let us know about your findings.

I have a 9m/27' Hends French Camou tapered leader (very long butt section) that I've been meaning to try with my 0 & 1wts. It too could probably be used as an intermediate, if treated with a sinking agent.

Have you tried poly leaders?

If I had to have an ultralight setup for sinking lines - I'd pick up one of these:

Cabela's Three Forks 7'6" 3 piece 3 weight
https://www.cabelas.com/product/Fishing/Fly-Fishing/Fly-Fishing-Rods|/pc/104793480/c/104721480/sc/105573780/Cabelas-Three-Forks-Fly-Rods/734547.uts?destination=%2Fcatalog%2Fbrowse%2Ffly-fishing-rods%2F_%2FN-1102568%2FNs-CATEGORY_SEQ_105573780

Then one of these:

Cabela's Wind River #1 mid arbor fly reels
https://www.cabelas.com/product/Fishing/Fly-Fishing/Fly-Fishing-Reels|/pc/104793480/c/104721480/sc/105572880/Cabelas-Wind-River-Fly-Reels/1307921.uts?destination=%2Fcatalog%2Fbrowse%2Ffly-fishing-reels%2F_%2FN-1102569%2FNs-CATEGORY_SEQ_105572880

Throw in some backing
https://www.cabelas.com/product/Fishing/Fly-Fishing/Fly-Lines-Backing/Lines-Backing|/pc/104793480/c/104721480/sc/104338980/i/105553080/Cabelas-Prestige-Hi-Vis-Fly-Line-Backing/732306.uts?destination=%2Fcatalog%2Fbrowse%2Flines-backing%2F_%2FN-1102366%2FNs-MIN_SALE_PRICE%3FWTz_stype%3DGNU

Then top it with the Rio Aqualux like this
https://www.cabelas.com/product/Fishing/Fly-Fishing/Fly-Lines-Backing/Lines-Backing|/pc/104793480/c/104721480/sc/104338980/i/105553080/Rioreg-Aqualux-Intermediate-Fly-Line/1884396.uts?destination=%2Fcatalog%2Fbrowse%2Flines-backing%2F_%2FN-1102366%2FNo-96%2FNs-MIN_SALE_PRICE%3FWTz_st%3DGuidedNav%26WTz_stype%3DGNP%26recordsPerPage%3D48

or head to your local fly shop and grab a Cortland Clear Camo 444 series line. They're less expensive than the Aqualux - about $50 on the high side, $35 or less on sale.

What distances are you casting that a full sinking line is preferable to a sink tip? Some lines come with 20+ sink tips, and if you add an AirFlo polyleader or Rio VersiLeader - you can add 5-15 feet of additional tip - and they range from floaters to type VII sinking stuff. I have a bunch of both - heavy on 5 and 10 footers, and one 15 foot 7ips sinker for my 7 weight rod for getting deep and pulling light flies down with it. Honestly, a 10' versileader and a 2-4 foot tippet have given me all the sinking I could ask for without adding split shot to the leader, add that combo to a typical 15' sink tip and you've got 27+ feet of sinking line/leader/fly combo to get under the surface.

FWIW - I stick to floaters on my true ultralight rods - sinking line work I do with 4 weight and heavier rods. For my 2 and 3 weight rods - I've found longer leaders and lightly weighted flies work well. Going too heavy with the 2 weight never ends up well.