Would you mind telling me what you mean by a pseudo-ladder? I.e., how it differs from a regular ladder?
(Overall, my approach is similar to yours.)
Certainly. Suppose you have created a bond ladder out of regular bonds, each of which has its own duration. You can then look at the ladder in its totality at any given point in time and find out what the effective duration of the whole ladder is. As each year passes, the effective duration of the entire ladder is shortened.
Using this concept, you can perform the near-equivalency by using 2 (or more) bond funds, each having different durations. Every bond fund publishes its current effective duration. For the current, effective duration you want to achieve, you simply hold the 2 bond funds in the correct proportions such that the total effective duration is what you're looking for.
TIPs bond funds are a special case because not all fund companies publish their effective durations based on "real yields" but instead publish based on "nominal yields", which isn't correct. There are sources that correctly calculate effective durations correctly. Some believe that even using nominal based duration is probably close enough.
Anyway, for myself I mapped out what duration I need every year (every quarter actually), and I adjust the proportions quarterly, if needed, though I've seen anywhere from monthly to annually being used. I think quarterly is "good enough" for what I want to achieve. Adjustments need to be made because the effective duration you want to achieve has shortened a little bit, but also because the durations reported by the individual bond funds move around a little bit over time. My spreadsheet tells me exactly how much of one fund I need to sell to buy more of the other. Takes all of about 5 minutes to do, though depending on whether you're using mutual funds or ETFs, you may have to wait a couple of days for settlement to happen before you make the new purchase.
Some people do this with simply a long duration bond fund and maybe an ultrashort duration bond fund. I think that's probably a little too coarse since bond yield curves don't follow a straight line all the way from longest to shortest duration. I start by using a long term bond fund and an intermediate bond fund. Eventually, as time goes by, the effective duration needed is less than what the intermediate bond fund is. At that point, I keep the intermediate bond fund and add a short bond fund. Again, at some point in time, the duration needed is less than the duration of the short bond fund, so I then add an ultra short bond fund.
That's basically it. It's not perfect. Obviously doing a continual rebalance will come closest to the "real deal", but sometimes good enough is good enough.
You do have some additional drag, too, because mutual funds do have expense ratios, though at least for nominal bond funds they're really small these days. Also true for TIPs funds, except for the only existing long duration TIPs fund available to most - that's LTPZ with an e/r of 0.20%. But you also don't have to deal with income being thrown off from a true ladder before you need the income. I just have both bond funds set to reinvest dividends/cap gains so I don't have to deal with that.
There are several threads over on bogleheads which discuss this concept.
Here's one that talks about doing this with TIPs (and it also refers to an earlier posting).
https://www.bogleheads.org/forum/viewtopic.php?t=240325
Finally - I have to add that there are many who are perfectly comfortable building true bond ladders. Nothing at all wrong with that. I'm not claiming that this method is in any way superior, likely slightly inferior. But I find it suits me. YMMV.
Cheers.