Is there a way to make an app where the user can dynamically add/config components?
I want to have a list of timers, perhaps - user can add/delete/edit MyTimer objects - or, a grid where the user can decide to have a "MyTimer: in a cell and add a "MyText" cell next to it for notes, that sort of templated per-user flexibility using app-specific components.
Just to make sure I understand, do you need this functionality in the builder or the actual app?
This would be in the actual app. It would be like an android widget. The app is a flexible daily-log, so you you get to choose what kinds of things are in your daily log (a location, a time, a number, etc).
Good to emphasize the "no limits" message but I'm trying to sort out whether adopting Triggr would make that easier or harder 
... I don't really have screenshots yet, just idea-scribbles. So I'll describe the app in more detail (probably too much, sorry) and maybe that will suffice...
The app idea is a logbook of templated Activities, where the Activities are specific to each user (my Activities might include 'jogging' and yours maybe 'parasailing' or 'visiting grandma'), for high-speed and moderate-consistency logging of recurring activities (going jogging, etc). There are two use cases to consider:
Making an entry
User has a set of buttons on the app main page, one button for each entry type ('jog', 'visit', whatever). Tap on button, get an input form with a set of controls (text, photo, etc), operate the controls and save the entry. Key issue is customization to the User's needs: every Activity can have a different set of controls from other Activities ('jog' is different fields from 'visit grandma'), and each User can have a different set of controls even for a same-named Activity (my 'jog' Activity is different from your 'jog')
So this leaves the question, how does the User define the Activity/fields...
Adding an entry type.
The User select an Add Entry Type button or menu entry and is presented with a
form allowing entry of some metadata (e.g., a title, a default location, etc) and a set of a few Templates. A Template is a set of possible fields in a layout; the User selects a Template, and then enables/disables individual fields in the template. This combination of Activity metadata and modified Template becomes the new Activity, and a button with the name of this Activity is added to the app splash screen.
Would this be an easy app to build and iterate using Triggr, or would I be pushing the tool too hard?
Based on what you described you can use Tiggr to build the app. Tiggr is a cloud-based mobile app builder - so as I mentioned above, anything can be built in Tiggr, no limitations. Tiggr makes is very easy to build apps but, having said that, the app still has to be built and tested. How easy - that depends on exact requirements (where are you going to save the data? In app or there is a service?) and of course user (developer) experience. Someone who has never developed a mobile app (or any Web app), it will take longer than someone who has prior experience. Does this make sense?
Just to throw this out there, we do have professional services team that could help you build this app.
Just to wrap up: there's to be a backend service holding the user's profile, but the app has to run off-network (out hiking, etc) so it'll need to use local storage with some kind of sync service.
Thanks; I'll start the trial soon and try it out. (If it works at all, and some test-marketing shows a need, then I'll probably be knocking on that PS door for a realistic version