Open-Ended Random List

I've been looking for a way to randomly select items from an unnumbered list of arbitrary length. I have an aversion to d100 lists, because often there are just too many items and it's hard to get familiar with them all, especially if each item is long and detailed. On the other hand, shorter lists are often too short. In any case, I often have a list of an odd number of items that won't fit into even a Zocchi dice-based table, or I want to go with a list as it stands, but be able to expand at any time.

Here's a method I may have sketchily described before:

1. Roll 1d6 +1d4.
2. Result of d4 is a:
   1. start at the top of the list and count down 1 to 6 items (d6 result).
   2. start at the middle of the list and count up.
   3. start at the middle of the list and count down.
   4. start at the bottom of the list and count up.

This handles a list of 18 to 24 items. For more, replace the d6 with a d8 (26 to 32 items), a d10 (34 to 40 items), a d12 (42 to 48 items), or a d20 (72 to 80 items). If you use two columns per page, change the d4 to a d8 and use this table for position and direction:

1. Top of Column 1, down.
2. Top of Column 2, down.
3. Middle of Column 1, up.
4. Middle of Column 2, up.
5. Middle of Column 1, down.
6. Middle of Column 2, down.
7. Bottom of Column 1, up.
8. Bottom of Column 2, up.

This doubles the capacity of the previous lists.

If you have multiple pages, instead of numbering the pages, you can use the above procedure to select a page; just change "top of list" to "first page", "middle of list" to "middle page", and "bottom of list" to "last page" and count forward or backward from the point indicated. If you also roll to select items from a given page, you could potentially have very long lists, indeed: 400 or so items in single-column lists across around 20 or so pages. Pages can thus be shuffled or replaced without changing the procedure.