By Sam Oliver

Published: 02:00 PM EST

The number of digital storefronts reflecting availability of Apple's high-end iMac configuration is dwindling this week in yet another sign that long-overdue updates to the all-in-one desktop line may be inching their way closer to market.

We picked up on the trend while making routine updates to our Mac Price Guide (also below) throughout the week. Having been dropped from MacConnection's catalog a bit earlier in the year, the 3.06GHz model more recently saw its availability run dry at several other resellers, namely MacMall, OnSale, and ClubMac.

Around the same time, Apple pushed lead times for the system out to 2 to 4 days, from 1 to 2 days, on its U.S.-based online store. The minimum wait is a bit longer at some of the company's international shops like those in Canada, France and Japan.

While these slight delays happen from time to time, more telling may be the model's absolute removal from Amazon.com's product catalog sometime in the past 48 hours. The retailer's product page for the system is now a dead end, meaning it has likely been yanked from the retailer's database of products permanently.

Amazon, which is believed to be one of the largest -- if not the largest -- online Mac resellers by volume, traditionally does not remove product entries due to lack of inventory, but rather when the product has reached the end of its life. Although new searchs for the 3.06GHz iMac on Amazon still turn up a couple of results, those systems are being offered through the retailer's affiliates and are not stocked by Amazon.

These oddities come just weeks after it was reported that Apple had advised some of its sales partners that supply of iMacs would grow constrained in the weeks that would follow. In particular, the 3.06GHz iMac was singled out as a model that was unlikely to see further production.

We put in some calls to various resellers reflecting no stock of the high-end config and were told in some cases that Apple had indicated fresh stock of iMacs would arrive sometime next week. Should those deliveries not pan out or not include the 3.06GHz model, it would be seen as a further sign that the much-anticipated NVIDIA-based iMacs with Mini DisplayPorts are on their way.

Also expected in the near term are updates to the Mac mini and Mac Pro. Expectations for each of these revisions are archived in full and in descending order by date on their respective topics pages: iMac, Mac mini, Mac Pro.