Event signups & registration with ubercart

There's a slew of Drupal signup modules which enable event-registration (including paying for, email notifications, etc). Here are a number of reasons I'd rather event-registration to be handled by Ubercart, rather than a host of standalone modules.

1. Ubercart has much more in the way of payment gateways, reports, etc. There is a snippet to integrate Ubercart with Signup so as to benefit from both worlds, but this will only work for Uber 5.x because it depends on Workflow_NG.
2. I am using Ubercart already on the site, & it becomes inconsistent for the client to have to manage purchasing info in two locations (Uber & Signup)
3. To setup Signup the way I want, I need to install seven separate signup modules, most of which haven't been upgrade to D6 -- my only barrier to upgrading.

My initial impression was that I'd be able to replicate all 7 modules using just Ubercart (maybe with the help of Rules or other modules); however, after playing with it for a few hours I hit a few substantial barriers.  My impression at this point is that it is impossible to replicate the Signup combo with Ubercart.  I'm hoping I'm wrong, so please comment & we'll discuss :)  Anyway, here's a list of my attempted signup solutions using Ubercart, what worked, and what didn't.

-- "Signup allows users to sign up (or register, as in register for a class) for nodes of any type." (including signup_pay functionality)

Doable.

1. From Ubercart, you'll just need Ubercart core, then whatever payment methods you want.
2. Add a new class at /admin/store/products/classes.
3. Add your Date field (so as to make this a registrable event) at /admin/content/types/your_type.

-- "Includes options for sending a notification email to a selected email address upon a new user signup (good for notifying event coordinators, etc.) and a confirmation email to users who sign up. Each of these options can be enabled and customized per node."

Almost doable.  There are sane defaults for email notifications, setup at /admin/settings/ca.  However, these options are global rather than per-node.  I'm not sure if there's a per-node email-notification solution in Ubercart.

--"When used on event nodes (with event.module installed and regular cron runs), it can also send out reminder emails to all signups X days before the start of the event (per node setting) and auto-close event signups X hours before their start (general setting)."

NOT doable.  I initially thought that this functionality would be doable via Rules; however, as of Drupal 6, the workflow-like triggers & actions for all Ubercart data is handled directly by Ubercart, and is not exposed to Drupal.  Without this data, neither trigger.module or Rules have any conditions, triggers, or actions to work with.  So while Rules can handle time-based workflows, the necessary data isn't exposed by Ubercart, rendering this functionality impossible.

--"Settings exist for restricting signups to selected roles and content types, and any single node can be enabled for signup 'on the fly'. Administrators can look at both a signup detail for one node, and a signup summary for all nodes."

Doable, but not as slick, using uc_discounts.  I haven't used this module, so I can't speak to the solution -- I'm basing this off a discussion I'd read, which framed it a bit as a nuisance to setup.

So from my experience, event registration can be handled by Ubercart, but there are some limitations in replicating the signup combo's functionality (most of which is extremely valuable).